The object of the proposed research is to explore and develop an animal model of addiction. The experiments test a behavioral theory which attributes addiction to a failure of coherence in the patterning of non- addictive alternatives. Addictive behaviors generally have value in themselves, independent of their context. But non-addictive behaviors generally have little or no value except in the context of a pattern of behavior extending widely in time. For example, smoking a cigarette is pleasurable to a smoker in a great variety of circumstances but not- smoking is valuable (in the sense that it increases health) only if it is consistently pursued over a long period of time. The subjects of the proposed experiments are very hungry pigeons choosing between small amounts of food delivered earlier or large amounts of food delivered later. Patterns of food delivery will be varied to determine the general characteristics of conditions under which pigeons will choose a delayed but larger reward over a smaller reward that immediately satisfies their craving for food. One these characteristics are known they may be brought to bear on drug cravings of both humans and non humans in analogous situations.